If you want to change multiple stickers at a time, there are two ways to do it:
Using imports
Add a column, titled "Display type", and use "Standard" as the value
Add another column, titled "Stickers" and then add in the emoji that you want to be used per row
In the PamPam map maker
Go to a spot in the section you want to change
Select the spot
While, it's selected enter "CMD+K" with your keyboard
Search for "Apply sticker to section"